Techniques for sending messages for system access are described. In one aspect, a user equipment (UE) sends a first message with power headroom and/or buffer size information for system access. A Node B determines at least one parameter (e.g., a resource grant, power control information, etc.) based on the power headroom and/or buffer size information. The Node B sends a second message with the parameter(s). The UE sends a third message based on the parameter(s), e.g., with uplink resources indicated by the resource grant, with transmit power determined based on the power control information, etc. In another aspect, the UE sends a radio environment report in the third message. The report may be used to select a cell and/or a frequency for the UE. In yet another aspect, the second message includes power control information, and the UE sends the third message based on the power control information.